Terahertz emission from indium oxide films on MgO substrates excited at a photon energy below the bandgap

Author

Estacio, Elmer ; Que, Christopher T. ; Awitan, Fritz C B ; Bugante, John I. ; De Vera, Chesca ; Azares, Jonathan ; De Vero, Jeffrey ; Somintac, Armando S. ; Sarmago, Roland V. ; Salvador, Arnel A. ; Yamamoto, Kohji ; Tani, Masahiko

Author_Institution

Res. Center for Dev. of Far-Infrared Region, Univ. of Fukui, Fukui, Japan

fYear

2011

fDate

Aug. 28 2011-Sept. 1 2011

Firstpage

455

Lastpage

457

Abstract

Indium oxide (In₂O₃) films grown on MgO substrates by thermal oxidation were excited by femtosecond laser pulses having photon energy lower than the bandgap. The emission of terahertz (THz) pulse was observed using time domain spectroscopy in the reflection-geometry excitation. Results show that THz generation saturates at an excitation fluence of ~400 nJ/cm². Although two-photon absorption has been ruled out, the actual THz emission mechanism and still has to be verified and is temporarily attributed to carriers from defect level absorption possibly being driven by a strain field due to the lattice mismatch between the In₂O₃ and the MgO substrate.

Keywords

indium compounds; laser beam effects; magnesium compounds; optical lattices; optical pulse generation; semiconductor thin films; In₂O₃; MgO; bandgap; femtosecond laser pulses; indium oxide films; lattice mismatch; photon energy; terahertz emission; thermal oxidation; time domain spectroscopy; Indium; Optical films; Oxidation; Photonic band gap; Substrates; Ultrafast optics;

fLanguage

English

Publisher

ieee

Conference_Titel

Quantum Electronics Conference & Lasers and Electro-Optics (CLEO/IQEC/PACIFIC RIM), 2011

Conference_Location

Sydney, NSW

Print_ISBN

978-1-4577-1939-4

Type

conf

DOI

10.1109/IQEC-CLEO.2011.6193807

Filename

6193807